Answer: B. 625nm−630nm 1.8V−2.4V
Answer analysis:
This question mainly examines the basic knowledge of the wavelength and voltage range of LED red light.
First, we need to understand the basic characteristics of LED (light emitting diode).
The color of LED is mainly determined by the wavelength of its light, which is related to the energy difference of electron transitions in the LED material.
For red LEDs, the wavelength of its light is usually longer and is located in the red region of the visible spectrum.
Next, we analyze the options one by one:
A. 525nm−530nm is actually closer to the wavelength of green LEDs than red, and the voltage range of 1.8V−2.0V is also low for LEDs, so option A is wrong.
B. 625nm−630nm is exactly in the common wavelength range of red LEDs.
However, although the voltage range of 1.8V−2.4V may be applicable to some LEDs, it may be slightly low considering that red LEDs usually have a higher forward voltage.
However, since we are mainly concerned about the wavelength and the voltage range is only used as a reference here, option B is correct in terms of wavelength.
C. 470nm−475nm This wavelength range is obviously shorter and closer to the wavelength of blue LEDs rather than red, so option C is wrong.
D. 625nm−630nm Although this wavelength range is also the wavelength range of red LEDs, the voltage range of 3.0V−3.4V is relatively high.
Although some high-brightness red LEDs may require such a voltage, this is not a common voltage range for red LEDs, so option D may not be accurate enough in terms of voltage.
In summary, we are mainly concerned about the wavelength of the LED.
Among the given options, only option B's wavelength range of 625nm−630nm is a common wavelength range for red LEDs.
Therefore, the correct answer is B.